Ejector



E. G. ROSS EJECTOR Feb. l1, 1941.

'Filed April 14, 1939 3 Sheets-Sheet 1 w9sY/67-M l. all

Emea G. 'R055 l ENToR ATTORNEY Feb. 11, 1941. E, G, Ross 2,231,090

EJECTOR Filed April 14, 1959 3 SheefS-Sheet 3 ATTORNEY u Patented Feb.11, 1941 UNITED STATES PATENT; OFFICE EJEcroa Application April 14,1939, Serial N o. 267,936

18 Claims.

This invention relates to ejectors, preferably I of the steam' jet type,operating at exceedingly high vacuums or at low absolute pressures.

During the operation of steam jet ejectors, when operating at lowabsolute pressures such as ls than LV2 mm., or when handling a gas thatwill freeze at relatively low pressures and temperatures, ice forms onthe inside of the steam nozzle and/or on the inside of the diffuser,choking the passageways and interfering with the efficiency of theejectors.

An object of the present invention is to provide means for heating thenozzle or diffuser or both, as conditions may require, to prevent the4formation ofsueh ice and the consequent reduction of the efficiency ofthe ejectors.

With these and other objects in view, as may appear from theaccompanying specification, the invention consists of various featuresof construction and combination of parts, which Will be rst described inconnection with the accompanying .,drawings, showing an ejector of thepreferred form embodying the invention, and the features forming theinvention will be specifically pointed out in the claims.

In the drawings: Figure 1 is a longitudinal section through an ejectorconstructed in accordance with ther present invention.

Figure 2 is a cross-section taken on the line 2 2 of Figure 1.

Figure 3 is a cross-section taken on the line 3 3 of Figure 1.

Figure 4 isa longitudinal section through a modied form of theinvention.

Figure 5 is a cross-section on the line 5-5 of Figure 4. y

Figure 6 is a fragmentary section of a, further modied form of theinvention, being a modiilca- 40 tion of the structure shown in Figures 4and 5.

' Figure '1 is a longitudinal section through a still Afurther modifiedform of the ejector and its heating means.

Referring more particularly to the drawings, and with particularreference to the preferred form of the invention shown in Figures 1 to 3inclusive, the ejector comprises the diffuser body I having the nozzlehead 2 attached thereto in any suitable manner, and the nozzle head 2has therein which opens into the inlet of the diffuser the diffuser inthe usual manner. The nozzle the air or gas inlet ongsuction passage 3formed structure 6 includes the nozzle 1, which is de- -tachablyconnected in any suitable manner, as shown at 8, to the steam inletconnection 9, which may or may not have an inlet chamber I0 therein, asdesired. The steam employed for operating 5 the ejector comes from anysuitable source (not shown)` through the steam inlet II and passesthrough the diverging bore I2 of the nozzle 1 into the diffuser 4.

Ejectors operating atlowfabsolute pressures, 1o such as less than 41/2mm. or handling a gas that will freeze at relativelylow pressures andtemperatures, have been found subject to impairment of their eiliciencyby the formation of ice in the bore I2 of the nozzle 1 near its outlet15 and/or in the diverging. converging bore I 2 of the diffuser 4. Toprevent the formation of such ice, the present inventionembodies meansfor heating the nozzle 1 'and/or the diffuser 4. p

In the structure shown in Figures 1 to 3 of the 20 drawings, a heatingjacket I4 is formed about the nozzle 1 providing a chamber I5 which hascommunication with the steam inlet of the nozzle 1 through a passage I6,so that live steam entering the chamber I0 or the inlet passage of theejector 25 will pass through the passage I6 into the chamber I5 and havedirect contact with the exterior of the nozzle 1 for heating it toprevent the accumulation of ice on its inner surface or the walls of thebore I2. The steam circulates through the 30 chamber I5 and passestherefrom through an outlet passage I1. In Figure 1 of the drawings theoutlet passage I1 is connected by a pipe I8 with the heating or steamchamber I9 which surrounds the diiuser 4. Ihe chamber I9 is formed 35between the diffuser 4 and the jacket-forming, `diiixliser-carryingjacket 20. The chamber I9 has an outlet 2| for the steam which may beopened to atmosphere or may be connected to anv desired point. 40

If it is so desired, the outlet I1 may open directly to atmosphere or toany other suitable point, and a separate pipe, as indicated in dottedlines at 22, may have direct connection with the steam supply pipe 23and the steam inlet 24 of 45 the chamber I9. A

In the modied form of the invention shown in Figures 4 and 5 of thedrawings the nozzle 1' is heated by means of a steam coil 3B, which iscoiled about the nozzle in contact therewith, and 50 is enclosed in theheating chamber 3| formed within the jacket I4'. The inlet end of thecoil 30 opens into the chamber or steam inlet passage I0', so that livesteam from the steam inlet will be delivered directly into the coil. Theoutlet end 55 of the coil is connected to the passage Il', which may beopen to atmosphere, or as shown in Figure 4, may be connected to theinlet end of the coil 33. The coil 33 is coiled about and contacts theouter wall of the diffuser 4', and is enclosed within the heatingchamber I9 formed about the diffuser 4 by the jacket 20'. The outlet ofthe coil 33 is preferably at the lower end of the chamber i9', as shownat 34.

As in the form of the invention shown in Figures 1 to 3 inclusive, thecoil 33 may receive its steam direct from the steam inlet pipe ,23'through a pipe connection such as the dotted line connection 22', atwhich time of course the outlet I'I'hof the coil 30 will not beconnected to the inlet of the coil 3 3 by means of the pipe I8'.

Figure 6 of the drawings shows a construction which is similar to theupper half or nozzle heating part of the structure shown in Figure 4,including a coil 36, which is coiled about the nozzle 1a, in contacttherewith, for heating the nozzle to prevent formation of ice on thenozzle. Unlike the structure shown in Figure 4, however, the inlet ofthe coil 36 is shown as passing out through the head 2a, and it hasconnection with any suitable supply (not shown) of a heating medium,which may be steam, hot water, or any available and suitable medium forimparting the necessary heat to the nozzle 1a to prevent the formationof ice therein. A similar arrangement may be employed in connection withthe coil 33 shown in Figure 4 by merely connecting the pipe 22' to anysuitable source of heating medium other than to the steam supply 23',without departing from the spirit of the present invention.

Figure '1 shows a still further modification of the means of heating thenozzle and/or the diffuser of the ejector. In this modified form anelectrical heating coil 40 is coiled about the nozzle 1b and a secondheating coil 4I is coiled about and in contact with the diffuser 4b.These coils 40 and 4| may be of any approved type of electrical heatingcoil, and they are enclosed in suitable jackets I4b and 20h to preventtheir engagement with the steam, air and/or gas passing through theejector. The energizing of the coils 40 and 4I may be through anysuitable medium,

and the coils may be' simultaneously energized,

such as by the closing of a single switch as indicated in solid lines at42, or they may be independently energized by independent switches andcircuits, as shown in dotted lines at 43 and 44.

From the foregoing description taken in connection with the accompanyingdrawings it will be apparent that various types of heating means widelymodified within the invention defined by I the claims. v

ejector is operating at low absolute pressures the inlets of said steamjackets receiving steam independently from the steam entering the inletof the ejector.

2. In an ejector, a nozzle; a diffuser, a steam jacket about said nozzlehaving an inlet and an outlet for heating steam, and a steam jacketabout said diffuser having inlet for steam whereby said nozzle anddiffuser may be heated to prevent formation of ice therein when theejector is operating at low absolute pressures, the outlet of saidnozzle enclosing steam jacket being connected to the inlet of thediffuser enclosing steam jacket.

3. In an ejector, a nozzle, said ejector comprising an inlet passage forsteam'to said nozzle, a steam jacket about said nozzle v'having an inletfor steam opening into said steam inlet passage whereby the nozzle maybe heated to prevent formation of ice therein when the ejector is0perating at low absolute pressures said jacket having a steam outletopening out independently o the steam passages of the ejector.

4. The method of preventing lowering of the eiliciency of an ejectoroperating at low absolute pressures by the formation of ice Within theejector which consists in applying heat to the parts of the ejectorsubject to excessive cooling action when the back pressure in theejector is reduced below the ice point.

5. The method of preventing lowering of the efficiency of an ejectoroperating at absolute pressures equal to or lower than four and one-halfmillimeters (4l/ mm.) by formation of ice withinv the ejector whichconsists in utilizing part of the operating steam delivered to theejector as a heating medium to heat the parts of the ejector subject toexcessive cooling action when the back pressure in the ejector isreduced sufficiently to permit formation of ice in the ejector.

6. The method of preventing lowering of einciency of an ejectoroperating at low absolute pressures by the formation of ice within theejector which consists in utilizing part of the operating steamdelivered to the ejector as a heating medium to heat the surfaces of theejector swept by the steam.

7. The method of preventing lowering of the efficiency of an ejectoroperating at low absolute pressures by the formation of ice within theejector which consists in utilizing part of the operating steamdelivered to the ejector as a heating medium to heat the nozzle of theejector and subsequently utilizing the nozzle heating steam to heat thediffuser of the ejector structure.

8. In an ejector, means to prevent the formation of ice on the surfacesof the ejector swept by operating steam when the ejector is operating atabsolute pressures lower than four and onehalf millimeters (4l/2 mm.)said means comprising steam jackets about the steam swept surfaces andhaving connection with the steam supply ofthe ejector, said jacketsconnected in series whereby the steam will pass successively from onejacket to the next in the series.

9. The combination with an ejector including a steam nozzle and adiffuser, of means to prevent the formation of ice on the surfaces ofthe ejector swept by the operating steam when the elector is operatingat absolute pressures lower than fur and one-half millimeters (4l/2mm.), said means carried by the ejector and arranged to deliver heat tothe steam swept surfaces.

10. The combination with an ejector including a steam nozzle and adiffuser, of means to. prevent the formation of ice on the surfaces ofthe ejector swept by the operating steam when the ejector is operatingat low absolute pressure, said means comprising means for deliveringheat from a source other than the steam passing through the nozzle anddiffuser to the surfaces swept by the steam fiowing through the nozzleand diffuser.

1l. The method of preventing lowering of the efficiency of an ejectoroperating at low absolute pressures by formation of ice Within theejector which consists in circulating part of the operating steam of theejector about the exterior surfaces of the parts of the ejector subjectto excessive cooling action when the back pressure in the ejector isreduced sufliciently to permit formation of ice.

12. In an ejector, a nozzle, a diffuser, means to prevent the formationof ice in the ejector when the ejector -is operated at low absolutepressure comprising a jacket about said nozzle, and means within saidjacket for heating the nozzle to counteract the chilling thereofeffected by the 10W pressure operation of the ejector.

13. In an ejector, a nozzle, a diffuser, means to prevent the formationof ice in the ejector when the ejector is operated at low absolutepressure comprising a jacket about said nozzle, means within said jacketfor heating the nozzle to counteract the chilling thereof effected bythe low pressure operation of the ejector, and a second jacket about thediffuser, and heating means Within the jacket surrounding the diffuserfor heating the diffuser to counteract the chilling thereof effected bythe low pressure operation of the ejector.

14. The combination with an ejector including a steam nozzle and adiffuser, of means to prevent the formation of ice on the surfaces ofthe ejector swept by the operating steam when the ejector is operatingat low absolute pressure, said means comprising heating coils coiledabout said nozzle and diffuser for delivering heat to the surfaces sweptby the steam flowing through the nozzle and diffuser, said heating coilsconnected in series to permit flow of a heating medium from one coil tothe other.

15. The combination with an ejector including a steam nozzle and adiffuser, of means to prevent the formation of ice in the ejector whenthe ejector is operating at low absolute pressures, said meanscomprising electrical heating coils coiled about said nozzle anddiffuser for heating the parts of the ejector subject to excessivecooling action when the back pressure in the ejector is reducedsufhciently to permit formation of ice.

16. The combination with an ejector including a steam nozzle and adiffuser, of means to pre vent the formation of ice within the ejector,said means including electrically operated heating means about thenozzle for heating the nozzle when the back pressure in the ejector isreduced sufficiently to permit the formation of ice.

17. The combination with an ejector including a steam nozzle and adiffuser, of means to prevent the formation of ice within the ejector,said means comprising electrically operated heating means about thenozzle and the diuser for heating the nozzle and the diffuser andprevent the formation of ice in the ejector when the back pressure inthe ejector is reduced sufficiently to permit the formation of ice.

18. The combination with an ejector including a steam nozzle and adiffuser, of means to prevent the formation of ice in the ejector, saidmeans comprising steam coils coiled about the nozzle and about thediffuser for delivering heat to the nozzle and the diffuser to preventthe formation of ice when the back pressure in the ejector is reducedsufficiently to permit the formation of ice therein.

- ELMER G. ROSS.

